Metallized synthetic spun yarn



July 30, 1963 w. G. SCHARF METALLIZED SYNTHETIC SPUN YARN Mauth@ Filed Sept. 50, 1960 LLFU IN V EN TOR. Marzi? G SC//AQF w Q//w Amy/Veys METALLIZED SYNTIETIC SPUN YARN Waiter G. Scharf, Ridgewood, NJ., assigner to Metal Film Company, Inc., New York, N.Y., a corporation of New York Filed Sept. 30, 1960, Ser. No. 59,728 11 Claims. (Cl. 23-72) This invention relates generally to metallized textile materials, and more particularly to the manufacture of staple fibers formed of synthetic met-allized ribbons and usable for spun yarn. This invention is a continuationin-part of my earlier application tiled June 18, 1956, issued March 7, 1961, as Patent No. 2,974,055.

'Ihe use of metallized threads in fabric design to enhance the Ibeauty of the fabric is of ancient origin. In order to tobviate certain drawbacks inherent in threads made entirely of metal or those having a core of natural iiber, it has been the practice in recent years to form such threads by combining met-al with synthetic materials of superior tensile strength.

In one known commercial form, a continuous lament is composed of two narrow plastic ribbons bonded together by adhesive, the interior surface of one ribbon being coated with a metal deposit. In .another commercial form, a strip of metal foil is sandwiched between two plastic ribbons and bonded thereto. In either laminated form, the ribbons may be made of cellulosic material, such as cellulose butyrate, although non-cellulosic lamina may also be used such as Mylar (polymerized ethylene glycol terephthalate).

Fabrics woven `of continuous metallized iilaments have a -ribboned surface and are limited in their design possibilities, particularly since the basic thread is flat, not round as with conventional threads. The resultant fabric does not have the hand or -appearance of fabrics formed with round libers. Moreover, the use of adhesive between the ribbon plies which form the filament gives the resultant thread a tendency to delaminate in the course of chemical or mechanical processing such as sanforizing, dyeing, commercial washing and `dry cleaning. Also adhesive acts to reduce the brilliance of the thread.

A more serious limitation of laminated metallized threads from the standpoint of textile design is that the practical use of such threads is conined to continuous iilarnent applications. While it is known to convert continuous lfilament thread of synthetic material into staple lengths which are Ithereafter spun into yarn, such conversion has not heretofore been possible with laminated metallized threads. Such threads, if cut into staple lengths, are excessively thick and heavy and cannot be spun effectively. They tend to be [thrown out of the spinner `and will not wrap around and interlock with each other.

Accordingly it is the principal object of the invention to provide staple iibers derived from a metallized synthetic tape and usable for spun yarn.

More specifically, it is an object of the invention to provide a composite metallized tape which is exceptionally thin and light `and is convertible into staple liber, the tape being constituted by a transparent base ribbon having a metal layer deposited thereon, the metal layer being coated with a transparent film which is related structurally to and has an atiinity for the base ribbon. A tape in accordance with the invention is produced entirely Without adhesives, it is inherently incapable of delaminait is highly iiexible and has improved tensile strength.

It is also an object of the invention to provide metallized staple tibers -iormed of composite material whose integrity is maintained when the bers lare processed chemically or mechanically.

Briefly stated, spun yarn .in accordance 'with the invention is fabricated by cutting into staple lengths and spinning fibers derived from a continuous tape formed by a transparent exible plastic ribbon coated on one side with a deposit of metal, the surface of the metal deposit being covered with a plastic solution or suspension which when dried and cured affords I'an adherent transparent film, the plastic coating being a material related structurally to the ribbon and having an affinity therefor.

For a better understanding of the invention as well as other objects `and yfurther features thereof, reference is made to the following detailed description to be read in conjunction with the -accompanying drawing.

In .the drawings:

FIG. 1 is a schematic -diagram showing the process in accordance with the invention adapted to produce a metallized synthetic web.

FIG. 2 is a sectional View of fone embodiment of a metallized tape according to the invention.

FIG. 3 is 4a sectional view of another preferred embodiment of a metallized tape.

FIG. 4 schematically illustrates one method for converting a tape of metallized material into staple liber.

FIG. 5 is a magnified -view of a single staple iiber.

FIG. 6 illustra-tes la spun yarn made of staple iiber in accordance with the invention.

Referring now to FIG. 1, there is shown a process in accordance with the invention for producing a metallized web which may be slit to form a relatively narrow tape, the tape then being .cut int-o ber lengths. A continuous web of transparent thermoplastic material 410 is drawn yfrom a supply roll 11 and is caused to travel thro-ugh a high vacuum chamber 12 wherein lone surface of the film is metallized. rIhe web may be constituted by cellophane, acetate, tri-acetate, acetate butyrate, polymerized ethylene glycol terephthalate (Mylar) or any other suitable transparent .and tlexible material capable of being vacuum-plated. The thickness of the web for ordinary yarn should not exceed 2 mils and is preferably of 1/2 mil thickness.

In the vacuum chamber 12, one surface of the iilm is metal-plated by gold, silver aluminum, magnesium, titanium, nickel tor any other metal, the thickness of the metal layer being molecular and not exceeding %0,00Uth of an inch. 'I`he deposition may be carried out by known thermal evaporation or cathodic sputtering techniques. In ther-mal evaporation, metal vapor is generated by direct heat such as an electric arc source or .a glowing tilamenrt. To effect maximum adherence of the plated iilrn, the metal atoms should pass linearly from their source to the surface to be coated and this requires the maintenance of pressures of about 10-4 Iof mercury in the vacuum chamber.

In' cathode sputtering, Ya high voltage is impressed between an anode and a cathode of the plating metal. The cathode is vaporized by positive-ion bombardment, some of the vapor diffusing laway lfrom the cathode and depositing on the web to be plated, The voltage requirements `depend on the nature of the cathode metal. At pressures of 0.01 to 0110 mm. of mercury necessary to maintain the glow discharge, the ordinary laws of diffusion prevail. After plating, fthe web is re-rolled on takeup drum 11 in preparation for the next step.

To produce a yarn having the color properties of the metal deposit, the metallized web is then coated on the metal side with a transparent plastic in solution or suspension which is related structurally to andhas an ailinity for the -web which is metallized. That is to say, the plastic coating must have substantially the same tensile strength 4and elongation characteristics as the web material. Since the metal layer is of molecular thickness it is inherently permeable to the liquid plastic coated thereon.

The plastic coating can be applied by a roller coater, a reverse roller coater, or by the llexographic or rotogravure process. By way of illustration, FIG. l shows a direct three roll coater. The coater, generally designated by numeral 13, includes a bath -14 for containing the liquid, a first roller 15 which is rotatable within the bath and acts to apply the liquid to a second roller 16 which engages the metallized surface of the web 10, the Web being pressed against the second roller by means of a third roller 17.

The wet plastic coating formed on the web 10 is then dried and cured by passing the web through a suitable oven 18 which is properly heated and vented lto drive olf ali solvents and at the same time to effect the curing of the coated material. For heating purposes, steam, gas

heat or infra-red radiation may be employed, as desired.

The temperature of the oven and the travel time therethrough are determined by the specific web and coating materials. The coating is further cured by cooling drums 19 `disposed at the opposite end of the oven. Cooling may be accomplished by a circulating water system or a refrigerant. Thereafter the metallized and coated web is longitudinally severed or slit in :a conventional slitter 20 into tapes each having la width appropriate to staple fibers.

In FIG. 2 there is shown' la section taken through the tape. The tape is composed of a thermoplastic base strip 21, a thin metall coating 22 being deposited thereon and a plastic lm 23 being intimately bonded to the surface of the metallized strip to form an integral structure. Preferably the strip is about l/2 mil in thickness and the film is yabout 1/s mil thickness, the thickness of the deposit being negligible. Thus the total thickness is less than one-thousandth of an inch.

The color or luster of the tape produced in the above- 4described technique is determined by the natural color of Ithe metal deposition. However, it is also possible to generate other colors -by adding a dye or pigment to the plastic coating fluid, in which event the resultant color in the finished tape is the combination of the metal and pigment hues. For example, as shown in section in FIG. 3, a gold eEect may be realized by a silver or aluminum metal deposit 22 in combination kwith a plastic coverin-g 23 having an' amber dye or translucent pigment therein. To have the gold effect on either side it is also necessary Vto color the non-metallized surface of the base strip and this is best vaccomplished by aapplying the pigmented or ldyed liquid plastic 24 to this side as well as the metallized side, so that a film is formed on both sides of the base strip.

As pointed out previously, it is important that the plastic coating on the metallized web be related structurally and have an ainity for the web material. Where 'the web material is constituted by Mylar, it has been found that an effective coating is one in which the basic make-up of the solids `are `approxinrrately as follows on a ratio basis per weight:

1 part Vinylite VAGH l part Vinylite VMCH 1 part nitrite rubber .12 ultra-violet light absorber The ratio basis of the above constituents may be varied without materially impairing the efficacy of the mixture by reducing the Vinylite VAGH to an extent not exceeding about 30%, and by increasing the Vinylite VMCH to an extent not exceeding about 30%. Alternatively, the Vinylite VAGH may be increased by 30% and the Vinylite VMCH decreased by 30%. However, the nitrite rubber should be held more or less constant, as well as the ultra-violet light absorber.

The light yabsorber acts aswan 'anti-oxidant relative to L?. the rubber and in lesser amounts than above indicated is not fully effective. On the other hand, an increased yarnount Would not signicantly improve the ultra-violet light resistance of the dried lilm laid down with the coating composition. The light absorber prevents discoloration `of the film.

'Ihe nitrite rubber is available commercially from several sources. The nitrite content may run between 30 to 36% and the balance made up of butadiene. This type of rubber is higher in sacro-nitrite content, giving a harder polymer which is necessary to add to the compositions for a non-blocking coating and one that will resist boilin-g of coating when the coated material is formed into metallic yarn and subjected to various dye and cleaning processes, etc.

The Vinylite VMCH is manufactured by Bakelite Corp. under their trade name, the chemical composition being as follows:

Vinylite VAGH is also manufactured by Bakelite Corp., the chemical constituents being the following:

Percent Vinyl chloride 91 Vinyl acetate 3 Organic material having hydroxyl group (2.6 times greater when calcul-ated as vinyl alcohol) 6 The function of the Vinylite VMCH is to effect 'adherence to metallic surfaces and also to plain polyester surfaces. The Vinylite VAGH gives better range for hardness and overall compatibility which allows the introduction of a wider range lof colors. v

The Vinylite VMCH does not tolerate the addition of many pigments or dyes, and resort is therefore had to VAGH for broader compatibility of colors to be added,

as Well Ias to good adhesion, along with a material that is hard, thereby imparting a non-blocking character to the coating film itself. Various types of light fast azo dyes,

-vat dyes and various types of pigment ldispersions are compatible in this mixture. i'

This mixture may be dissolved in a straight ketone sys-V tem, such as acetone or where high volatility and evoparation of solvents is desired. For general coating operations on reverse -roll coaters, the solvent system may be 2/3 methyl ethyl ketone and 1/3 varomatic hydrocarbon, such as toluol solvent. The solids may range between 18 to 23% for a low viscosity mixture.

A metallized tape formed in `accordance with the above described process and including a Mylar base or web will afford increased yardage per pound of Mylar las cornpared with conventional laminated structures since only one ply of Mylar is entailed. And since no adhesive ris employed, the plastic coating being integrally bonded to the web, lche tape and the staple fibers derived cannot delaminate.

As pointed yout above, the broad metallized web is slit down to tape size. In practice, a web having a 48 inch width is cut down to a narrow tape Whose width is equal to the preferred length of staple fiber. Thus, the width of the tape may run between about one and three inches,

as is the case with standard short and long staple lengths Y in natural bers, such as cotton or Wool.

As shown in FIG. 4, the continuous tape 25 is fed through a staple cutter or chopper which may take the form of a cutting drum 26 having an array of radially extending blades Z7 arranged circumferentially thereon. The blades, which cut the tape transversely against a platen 2S, are spaced from each other rat distances equal to the desired width of the staple fibers 29 which are cut from the tape. The width fof the staple ber preferably is about 1/120 of an inch. Alternatively a reciprocating blade may be used to chop the tape into fibers. The individual staple bers Iare extremely thin and ylight and are readily spun into yarn by known spinning techniques such as those described in Man Made Textile Encyclopedia, edited by J. J. Press land published by Textile Book Publishers, Inc. (f1959). The objects of spinning are to reduce the bulk fed to the desired size, to insert twist and to produce a rm package suitable for the next operation. A spun yarn is a continuous strand of brous material which has received its nal attenuation and has been twisted to give it suicient strength or other desired characteristics.

In `order to improve the spinning qualities of the staple bers of metallized material, the tape is cut by blades having a serrated cutting edge, whereby as shown in FIG. 5, the edges 29a and 29b are similarly corrugated or serrated to augment the interlocking characteristics of the bers. While the individual bers are at, the yarn resulting from spinning these bers are generally round, the spun yarn, 'when woven, provides a fabric having a soft hand an appearance which 'diers signioiently from that obtained with continuous metallized at threads. It has been found that the spun metallized yarns provide a rich and warm metallic glitter not achieved by any other form of yarn.

It is also possible to intermix metallic staple bers of different colors to provide unusual col'or effects, or to combine metallic staple bers with conventional staples of natural or synthetic material to produce radiant spots of color and to achieve other remarkable decorative effects. The metallized staple bers may also be combined with paper in Ia paper making machine, the bers being deposited on the wet web in the machine and forming an integral part of the nished sheet when the web is dried.

The metalllized staple bers are also usable as a rellective tinsel or chaff which may be jettisoned from lan aircraft to effect deceptive jamming effects in connection with radar or other military detection devices. The extreme lightness 'of the chad causes it to float in the atmosphere for long periods.

The plastic lm for the metallized carrier or web material may also be derived from polyester resins and epoxies in solution which when dried land cured `form a lrn having a strong anity for the carrier particularly when the carrier is Mylar. The metallized staple bers may be intermixed with non-metallic bers of natural or synthetic material to form composite spun yarns, as shown in FIG. 6, spotted with metal land having a decorative glitter. Such non-metallic staple bers as wool, silk and cotton may be used in this connection. The spun yarn is made up of metallized bers Fm and non-metallized bers Fn.

While there have been shown what are considered to be preferred embodiments :of the invention, it will be manifest that many changes and modications may be made therein Without departing from the essential spirit of the invention. It is intended, therefore, in the annexed claims to cover all such changes and modications as fal-l within the true scope of the invention.

What is claimed is:

1. rIhe method of fabricating metallized spun yarn comprising the steps of slitting a web of metallized plastic material into tapes having a width equal to the length of staple bers and having a thickness not in excess of about 2 mils, said web being constituted by a base layer of synthetic material having a metal deposit thereon coated by a plastic lm, cutting said tapes transversely at spaced positions into staple bers of narrow width whose longitudinal edges are serrated to facilitate interlocking of said bers, and spinning said bers into yarn.

2. The method, as set yforth in claim 1, wherein said web has a thickness of less than one mil.

3. The method, as set forth in claim l, wherein said tape has a width of between l to 3.5 inches.

4. A metallized spun yarn constituted by staple bers each of which is of a thickness not in excess of about 2 mils and is formed by a base of transparent exible thermoplastic material having a -met-al deposit coated thereon and a layer of plastic lm directly adherent to said deposit and of a material rel-ated structurally to said base vand having an ainity therefor, said bers being formed by at strips having serrated longitudinal edges.

5. A yarn, as set forth in claim 4, wherein said bers have a thickness of less than one mil.

6. A yarn, as set forth in claim 4, wherein said bers have a width in the order of 1/120 of an inch.

7. A metallized spun yarn constituted Iby staple bers each of which is of -a thickness not in excess of about 2 mils and is formed of a base of transparent exible thermoplastic material having a metal deposit coated on one side thereon, a rst layer of pigmented plastic lm -directly adherent to said deposit and a second layer of pigmented plastic lm directly adherent to the other side of said base, said lms being formed of liquid plastic which is dried and cured and which is of a material related structurally to said base and has an anity therefor, said bers being formed by at strips having serrated longitudinal edges.

8. The method of forming metallized spun yarn comprising t-he steps of fabricating a tape having a width equal to the length of staple bers and a thickness not in excess of about 2 mils and formed by a transparent flexible plastic ribbon coated on one side with a metal deposit whose surface is covered with a liquid plastic which when dried and cured alords an adherent transparent lm of a material related structurally to the ribbon and having an anity therefor, cutting said tape into staple length bers whose longitudinal edges are serrated to facilitate interlocking thereof, and spinning said metallized bers with nonrnetallized bers to form a `composite spun yarn.

9. T-he method Ias set forth in claim 8, wherein said non-metallized bers are of wool.

l0. The method as set forth in claim 8, wherein said non-metallized bers are of silk.

11. The method as set forth in claim 8, wherein said non-metallized bers are of cotton.

References Cited in the le of this patent UNITED STATES PATENTS 2,508,852 Blumeld May 23, 1950 2,714,569 Prindle et al Aug. 2, 1955 2,926,415 Griin Mar. 1, 1960 2,963,850 Rosenblatt Dec. 13, 1960 

1. THE METHOD OF FABRICATING METALLIZED SPUN YARN COMPRISING THE STEPS OF SLITTING A WEB OF METALLIZED PLASTIC MATERIAL INTO TAPES HAVING A WIDTH EQUAL TO THE LENGTH OF STAPLE FIBERS AND HAVING A THICKNESS NOT IN EXCESS OF ABOUT 2 MILS, SAID WEB BEING CONSTITUTED BY A BASE LAYER OF SYNTHETIC MATERIAL HAVING A METAL DEPOSIT THEREON COATED BY A PLASTIC FILM, CUTTING SAID TAPES TRANSVERSELY AT SPACED POSITIONS INTO STAPLE FIBERS OF NARROW WIDTH WHOSE LONGITUDINAL EDGES ARE SERRATED TO FACILITATE INTERLOCKING OF SAID FIBERS, AND SPINNING SAID FIBERS INTO YARN. 